Bis-n-cyclopentadienyl alkyl and aryl complexes

The known complexes in this class are shown in Table 23. The bis-Ji-cyclopentadienyl titanium alkyls and aryls are considerably more stable to heat, oxygen and hydrolysis than are the alkyl titanium halides. 

In contrast, the mono-7c-cyclopentadienyl trimethyl titanium and triphenyl titanium complexes are very readily oxidized and hydrolysed [70,71]. 

The greater overall stability of the bis- -cyclopentadienyl complexes probably arises mainly from an increased luetic stability rather than from any large increase in the Ti-o-carbon bond energies. 

The monomethyl zirconium complex, 7.17, is rapidly hydrolysed although the compound is thermally quite stable, 191-193° d [72]. The 

Reaction of ( -CsH5)2ZrCl2 with triethylaluminium is thought to give the unstable binuclear complex (af-CsHs)2ZrCl—CH2CH2—ClZr(at-C5Hs)2 [726]. 

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